This invention relates in general to universal joint assemblies for vehicular drive train systems. In particular, this invention relates to an improved structure for retaining the bearing cups within the associated recesses of a half round end yoke.
Universal joint assemblies are well known devices that provide a driving connection between two members adapted to rotate about non-aligned axes of rotation. Universal joint assemblies are widely used between rotatable drive shaft sections in vehicle drive train systems. A typical universal joint assembly includes a cross having a central body portion with four cylindrical trunnions extending outwardly from the cross. The trunnions are oriented in a single plane and extend at right angles relative to one another, and the trunnions have a common intersection at the center of the central body portion. A hollow cylindrical bearing cup is mounted on the end of each of the trunnions. Needle bearings or similar means are provided between the outer cylindrical surfaces of the trunnions and the inner cylindrical surfaces of the bearing cups to permit relative rotational movement between the trunnions and the bearing cups. The bearing cups that are mounted on an opposed pair of the trunnions can be connected to a first end yoke secured to an end of a first drive shaft section, while the bearing cups that are mounted on a second opposed pair of the trunnions can be connected to a second end yoke secured to an end of a second drive shaft section.
Typically, the first and second end yokes can be classified as one of two well known structures, namely, a full round end yoke and a half round end yoke. A full round end yoke includes a pair of opposed arms having respective cylindrical openings formed therethrough, within which the opposed bearing cups are inserted. Flat retaining members are usually provided over the outer ends of the bearing cups for retaining them within the associated cylindrical openings. A half round end yoke includes a pair of opposed arms having respective semi-cylindrical recesses formed therein, within which portions of the opposed bearing cups are received. Retaining straps are usually provided about the circumferential sides of the bearing cups for retaining them within the associated semi-cylindrical recesses.
A typical structure for a retaining strap for use with a half round end yoke consists of a stamped plate or similar member including a curved central portion having a pair of end portions extending outwardly therefrom. The curved central portion of the retainer strap is generally semi-cylindrical in shape so as to conform with the outer surface of the bearing cup. The end portions of the retainer strap have respective holes formed therethrough that can be aligned with threaded bores formed in the arms of the half round end yoke. Threaded bolts or similar fasteners extend through the holes formed through the end portions of the retainer strap into cooperation with the threaded bores formed in the arms of the half round end yoke so as to secure the retainer strap thereto. In this manner, each of the bearing cups is retained within its associated semi-cylindrical recess of the half round end yoke by the retainer strap. Although known retainer straps have been used effectively for many years, it would be desirable to provide an improved structure for retaining the bearing cups within the associated recesses of a half round end yoke.
This invention relates to an improved structure for retaining the bearing cups within the associated recesses of a half round end yoke. The half round end yoke includes a pair of opposed arms, each of which terminates in an end surface having a generally semi-cylindrical recess and a pair of threaded bores formed therein. A cross includes a central body portion having four cylindrical trunnions extending outwardly therefrom. A bearing cup is rotatably mounted on the end of each of the trunnions. The cross is initially positioned adjacent to the half round end yoke such that a pair of the bearing cups is received in the semi-cylindrical recesses formed in the arms. Then, a retainer strap is positioned adjacent to the cross and the half round end yoke. The retainer strap includes an elongated central body portion having a pair of transversely extending retainer portions. Each of the retainer portions includes a curved region having a pair of end regions extending outwardly therefrom. Each of the curved regions has a generally semi-cylindrical inner surface formed therein. The semi-cylindrical inner surfaces of the curved regions of the retainer strap receive portions of the first pair of the bearing cups therein. The end regions of the retainer portions have respective holes formed therethrough that are sized to be aligned with threaded bores formed in the arms of the half round end yoke. Threaded bolts can then extend through the holes formed through the end regions of the retainer strap into cooperation with the threaded bores formed in the arms of the half round end yoke to secure the retainer strap thereto. In a first embodiment of the invention, each of the arms of the half round end yoke has a retaining tang formed thereon that positively restrains the bearing cups from being removed from the cross. In a second embodiment of the invention, each of the end regions of the retainer strap has a retaining tang formed thereon that positively restrains the bearing cups from being removed from the cross. The central body portion of the retainer strap extends between the two retainer portions thereof to increase the overall rigidity of the half round end yoke, which minimizes undesirable relative movement of the two arms and provides increased support to the cross, resulting in better bearing life and increased strength to the universal joint. In a third embodiment, a stiffening reinforcement is formed integrally with the arms of the yoke and extends between the opposed arms thereof.